Master's Theses

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    Development of multifunctional tick repellent textiles
    (2016-09) Akbar, Wazir; Başım, Gül Bahar; Başım, Gül Bahar; Yaralıoğlu, Göksenin; Nizamoğlu, S.; Department of Mechanical Engineering; Akbar, Wazir
    This thesis focuses on smart textile manufacturing with tick repellency through encapsulation of the natural extracts and applying them onto the fabric surfaces. Tick-borne encephalitis (TBE) is a human viral infectious disease involving the central nervous system. TBE cases in Europe have steadily increased over the last few decades. The disease is most often manifested as meningitis (inflammation of the membrane that surrounds the brain and spinal cord), encephalitis (inflammation of the brain), or meningoencephalitis (inflammation of both the brain and meninges). According to the World Health Organization 35-58% of TBE patients suffer long-term neurological problems, such as various cognitive or neuropsychiatric complaints, balance disorders, headache, dysphasia, hearing defects, and spinal paralysis, and 2% die from the disease. Consumer demand for hygienic clothing and active wear has created a substantial market for anti-tick and anti-microbial textile products. Therefore, it is an urgent need to find novel protective methods and/or products that can prevent or minimize the risks of the bites of these deadly insects, and consequently contributing to improvement of human health. Innovative textile products are continuously being developed and introduced to the market such as the ones with long-lasting fragrances and skin softeners, medical applications such as antibiotics, and antimicrobial agents for medical textiles. These are some applications for which clothing manufacturers utilize resources to add value to textiles in order to increase their competitiveness, improve market dynamics and enable economic growth of the industry. In this thesis work, textiles decorated with nano-micro capsules encapsulating bioactive oils, have been developed and studied for their anti-tick properties to cure and/or prevent the spread of tick-borne diseases. Encapsulation techniques make use of microcapsules which act as small containers of liquids to be released from the inner core under controlled conditions to address a specific purpose. Empty nano-capsules and capsules with eucalyptus oil as the core ingredient encapsulated by diblock co-polymer: polyethylene glycol-polycaprolactone (PEG-b-PCL) shell, were prepared using solvent evaporation technique. PEG-b-PCL is biodegradable polymer and has been used for its non-toxic nature, ability of maintaining good mechanical integrity until degraded and being capable of controlled rates of degradation. The developed capsules were characterized based on their surface morphology, size, size distribution, surface charge and controlled release. The capsules synthesized in lab along with commercially available polyuria based capsules have been applied to the textile selected, for tick repellency. In order to systematically study the tick repellency through capsules attachment the textile properties were thoroughly studied initially. For the determination of the best suited textile five different textile samples were studied in the first phase. The textiles studied are (i) %100 carded cotton, (ii) %100 combed cotton, (iii) %100 polyester, (iv) %100 viscose and (v) %100 tencel. Based on the fundamental understanding of the interaction forces it is believed that hydrophobicity should help enhance the attachment of capsules to the textile surfaces due to the hydrophobic-hydrophobic interactions. As a second mechanism, we also concentrated on the electrostatic attraction by tuning the surface charge of the textile and the capsules opposite. Cotton and polyester and their blends were chosen for further study due to their wide availability, use in sports outfits which is also the focus of this project. In addition these fabrics have relatively higher contact angles of 123.38º + 3.91º (cotton) and 121º + 5.83º (polyester) indicating hydrophobic nature with DI water after treatment in water repelling finishing solution. In the second phase a design of experiment (DoE) was conducted in order to determine the best textile composition and concentration of silicon in the finishing solution. The DoE revealed 13 tests to be performed for the design of optimum surface properties to enable maximum micro/nano-capsule adherence to the textile samples. The optimization of the responses in DoE was focused on higher hydrophobicity and higher negative surface charge in order to get more amount of positively charged silicon adsorbed. The optimization led to higher desirability for 100% cotton fabric treated with higher silicon content in the finishing solution to maximize the capsules attachment. However, a blend of %65 cotton and %35 polyester was chosen which is suitable for the sports outfits. Yet it has been prepared by weaving cotton fibers on top while polyester fibers on the bottom surface. The idea of this weaving style helps maximize the capsule attachment ability of textile while reducing the need for ironing, which can deform the capsules. The selected textile was treated, sprayed on cotton side, with the prepared nano-micro capsules loaded with eucalyptus oil. The attachment of capsules to the textile was studied by change in the pre and post spray weight of textile. The capsule attachment results from weight difference are in good agreement with predicted capsules attachment obtained from DoE study for a specific combination of textile composition and the concentration of silicon in the finishing solution. In summary, an optimal textile composition and weaving style was determined in this study to maximize the capsule attachment ability for tick repellency. It was observed that there is a good correlation between the hydrophobic and electrostatic nature of the capsules and the textile surface.